Interventional surgery causes small traumas to the human body and has a low invasion degree, which is a medical technology rapidly developed and popularized in recent years. Generally, with the help of an interventional medical sheath (such as a delivery sheath, a guide sheath and the like), a channel is established between a lesion site in the body of a patient and operating end of the outside, and is used for guiding a medical device, medicines, an device and the like to the lesion site. The interventional medical sheath has a proximal end and a distal end, the distal end can enter the vessel system of the human body after loading therapeutic medicines and devices, and the proximal end is connected with the operating handle. In use, a wire guiding track is generally pre-established, the distal end of the sheath or the distal end communicated with another auxiliary device punctures through and enters the vessel, and by utilizing the operating handle, the doctor controls the distal end of the sheath to move to the site along the pre-established wire guiding track, withdraws the sheath, and then releases the medicines, the device, and the like.
In consideration of the intricate characteristic of the vessel system of the human body and remote operations, the sheath generally should have sufficient axial force and excellent compliance. Before reaching the lesion site, due to the compliance of the sheath, the distal end of the sheath can adaptively adjust to a bending direction to comply with the vessels of the body when the distal end of the sheath advances along the wire guiding track under the pushing action applied by the doctor.
For example, the Chinese patent with the publication number of CN103446655A discloses an adjustable bent sheath and a delivery system having the same. The adjustable sheath comprises a tube body, the tube body has a distal end and a proximal end, reinforcing and traction wires are axially arranged in the tube wall of the tube body, the distal end of the traction wire is fixed at the distal end of the tube body, and the proximal end of the traction wire extends from the tube body and is connected with an operating handle. The adjustable bent further comprises an expansion section communicated with the tube body, and the expansion section is connected with one side of the distal end of the tube body and is used for accommodating an implantable device (such as a shape memory alloy stent and the like).
In such technology, in order to improve the connection strength between the expansion section and the tube body, the expansion section and the tube body are connected by using a thickened transition section, thereby solving the problem of connection strength between the expansion section and the tube body.
However, in order to ensure the compliance of the expansion section to a maximum extent after the expansion section loads a device, in most cases, the expansion section is a pure plastic sheath without adding a net-shaped reinforcing layer capable of influencing the compliance and the diameter, and the expansion section still is a part with the weak tensile property in the whole sheath.